On June 4, 2009, management of Electro Scientific Industries, Inc., (ESI) announced that it will extend
its temporary pay reduction program currently in effect for its executive management, through September 30, 2009. The current pay reduction program was previously scheduled to expire on June 30, 2009. During this pay reduction period,
ESIs President and Chief Executive Officers salary will be reduced 15% and the Vice Presidents salaries each will be reduced 12%.

On February 17, 2009, management of Electro Scientific Industries, Inc., (ESI) announced that it will
implement a temporary pay reduction program for its executive management, beginning March 1, 2009 and continuing through June 30, 2009, after its current pay reduction program expires on February 28, 2009. During this period,
ESIs President and Chief Executive Officers salary will be reduced 15% and the Vice Presidents salaries each will be reduced 12%.

On
January 20, 2009, Electro Scientific Industries, Inc. (the Company) issued a press release announcing unaudited preliminary financial information for the third quarter of fiscal 2009. A copy of the press release is furnished
herewith as Exhibit No. 99.1.

The information contained under Item 2.02 in this report and in the exhibit 99.1 attached to
this report is being furnished to the Securities and Exchange Commission and shall not be deemed filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the Exchange Act), or otherwise
subject to the liability of that Section, or incorporated by reference in any filing under the Exchange Act or the Securities Act of 1933, as amended (the Securities Act), except as shall be expressly set forth by specific reference in
such a filing.

On December 8, 2008, Electro Scientific Industries, inc. (the Company) entered into a Voting Agreement (the Voting Agreement) with The D3 Family Fund, L.P., The D3 Family Bulldog Fund, L.P., The D3 Family
Canadian Fund, L.P., The DIII Offshore Fund, L.P., Nierenberg Investment Management Company, Inc., Nierenberg Investment Management Offshore, Inc. and David Nierenberg (collectively, the Shareholders). The Shareholders beneficially own
shares of the Companys common stock.

The Voting Agreement provides (among other things) that if, on the record date with respect to
any meeting of the shareholders of the Company (however called) or any written action by consent of such shareholders, the Shareholders collectively Own (as defined in the Voting Agreement and used in this Item 1.01 with the same
meaning) issued and outstanding shares of Company common stock that, in the aggregate, exceed 15% of the total issued and outstanding shares of as of such record date (the number of shares collectively Owned by the Shareholders as of such record
date that exceeds 15% of the total issued and outstanding shares as of such record date being referred to in the Voting Agreement, and this Item 1.01, as the Excess Shares), then, at any such meeting or in any such consent, the
Shareholders are obligated to cause the number of Excess Shares Owned by them to be voted (whether in favor or against, as applicable) in accordance with the recommendation of the Companys Board of Directors. The Voting Agreement also provides
(among other things) that any transfers of Company securities Owned by any Shareholder to any one or more of certain specified types of transferees, and any acquisitions of Company securities by certain persons or entities with which any Shareholder
is affiliated or associated (by reference to criteria set forth in the Voting Agreement), are conditioned on the transferee(s) or acquiror(s) agreeing in writing to be bound by the Voting Agreement as Company shareholders. The Voting Agreement
further provides (among other things) that it will remain in effect for a minimum of three years, after which it will terminate at such time as all required parties to the Voting Agreement as Company shareholders collectively cease to Own at least
15% of the then-total issued and outstanding shares of Company common stock. The Voting Agreement is filed as Exhibit 10 hereto.

Item 3.03

Material Modification to Rights of Security Holders

On
December 8, 2008, the Company amended the Amended and Restated Rights Agreement, dated as of March 1, 2002, between the Company and Mellon Investor Services LLC, as Rights Agent (the Rights Agreement), to make certain
clarifications with respect to the definition of Acquiring Person and to provide that if a person is deemed to be beneficial owner of shares issuable pursuant to an agreement to which the Company is a party, all of the shares issuable by
the Company pursuant to such agreement shall be deemed outstanding for determining the percentage of the persons total beneficial ownership. The Third Amendment to Amended and Restated Rights Agreement is filed as Exhibit 4 hereto.

The Agreement and Plan of Merger and Reorganization (the Merger Agreement), dated as of October 15, 2008, among Electro
Scientific Industries, Inc. (ESI), Zirkon Merger Sub, LLC and Zygo Corporation (Zygo), contemplates that two ESI directors will resign at the closing of the merger, with the ESI Board of Directors at closing to consist of
eleven members, three of whom would be new directors designated by Zygo. Accordingly, on December 2, 2008, Gerald Taylor and Keith Thompson resigned as directors of ESI effective immediately prior to and contingent upon the closing of the
merger and the board of directors of ESI appointed each of Eugene G. Banucci, Youssef A. El-Mansy and Bruce W. Worster directors of ESI, effective and contingent upon the closing of the merger. The three appointees were designated by Zygo
in accordance with the terms of the Merger Agreement.

Item 5.03

Amendment to Articles of Incorporation or Bylaws; Change in Fiscal Year

On December 2, 2008, the board of directors of ESI amended Section 2.1 of the Companys 2004 Restated Bylaws, effective immediately prior to the merger, to increase the maximum size of the board of
directors from ten to eleven. Section 2.1 of the 2004 Bylaws, as amended, is filed as Exhibit 3.1 hereto.

Item 9.01

Financial Statements and Exhibits

(d) Exhibits

The following exhibits are filed herewith and this list is intended to constitute the exhibit index:

On December 3, 2008, Electro Scientific
Industries, Inc. (ESI) announced that the Federal Trade Commission has granted early termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, with respect to the previously announced merger
agreement among ESI, its wholly owned subsidiary Zirkon Merger Sub, LLC and Zygo Corporation. A copy of the press release is attached as exhibit 99.1 hereto.

Item 9.01

Financial Statements and Exhibits

(d) Exhibits

The following exhibits are filed herewith and this list is intended to constitute the exhibit index:

On November 25, 2008, management of Electro Scientific Industries, Inc. (ESI) implemented a temporary pay reduction for
ESIs President and Chief Executive Officer and Vice Presidents. The pay reduction will begin December 1, 2008 and end February 28, 2009. During this period, the President and Chief Executive Officers salary will be reduced 15%
and the Vice Presidents salaries each will be reduced 12%.

On
October 15, 2008, Electro Scientific Industries, Inc. (the Company) and its wholly owned subsidiary, Zirkon Merger Sub, LLC (Merger Sub) entered into an agreement and plan of merger and reorganization (the Merger
Agreement) with Zygo Corporation (Zygo). The Merger Agreement is attached as exhibit 2.1. Under the Merger Agreement, Zygo will merge into Merger Sub, with Merger Sub surviving, and each share of Zygo common stock will be converted
into the right to receive 1.0233 shares of common stock of the Company. Options and other rights to purchase Zygo common stock will similarly be converted into the right to purchase Company common stock, except that options to purchase Zygo common
stock with an exercise price greater than $40 per share will be terminated.

Completion of the Merger is subject to customary conditions, including
approval by the shareholders of each of the Company and Zygo and specified regulatory approvals.

The October 16, 2008 press release announcing the
Companys entry into the Merger Agreement is attached as exhibit 99.1.

Item 9.01

Financial Statements and Exhibits

(d) Exhibits

The following exhibits are filed herewith and this list is intended to constitute the exhibit index:

ExhibitNumber

Exhibit Title

2.1

Agreement and Plan of Merger and Reorganization by and among Electro Scientific Industries, Inc., Zirkon Merger Sub, LLC and Zygo Corporation dated as of October 15, 2008

On
August 20, 2008, Electro Scientific Industries, Inc. (ESI) amended the Amended and Restated Rights Agreement, dated as of March 1, 2001, between ESI and Mellon Investor Services LLC to permit Third Avenue Management LLC to
beneficially own up to, but not including, an aggregate of 19.99% of the outstanding shares of ESIs common stock. This amendment reflects the change of the identity of the manager of Third Avenue Funds from EQSF Advisors, Inc. to Third Avenue
Management, LLC.

Item 9.01

Financial Statements and Exhibits

(d) Exhibits

The following exhibits are filed herewith and this list is intended to constitute the exhibit index:

Exhibit Number

Exhibit Title

4

Second Amendment to Amended and Restated Rights Agreement, dated as of August 19, 2008, between Electro Scientific Industries, Inc. and Mellon Investor Services LLC.